For example, for a carcass member used in a radial tire, as a carcass member (carcass ply), there is used a so-to-speak topping sheet topped (covered) with rubber by constituting a core member by a number of pieces of cords for reinforcement.
In a background art, such a carcass member for a tire is fabricated by using a so-to-speak cord fabric having a comparatively wide width woven by constituting warp by a cord mainly made of a synthetic fiber constituting the core member and roughly striking slender weft serving as a connection at necessary intervals in a warp direction and passing the cord fabric through a calender roll of a comparatively large-sized equipment to top rubber thereto.
However, according to the above-described method, there is needed a wide area for stocking a material or a fabricated carcass member such as a storage space of a material of the cord fabric or the like before being topped by the calender roll, a storage space of a carcass member after having been topped or the like, and personnels are needed for transportation or the like. Therefore, a problem is posed in a productivity and it is disadvantageous for moving tires of many product kinds and small amount production. Further, although it is conceivable to downsize the calender apparatus, by simply downsizing the calender apparatus, a time period required for topping rubber remains unchanged, and therefore, it is rather disadvantageous in view of operation rate.
Therefore, in recent years, it is proposed to form a carcass member in a strip-like shape having a comparatively slender width by aligning a plurality of pieces of cords for reinforcement and topping rubber thereto without using a cord fabric, thereby, forming a carcass layer of a tire.
For example, Patent Reference 1 and Patent Reference 2 propose to form a carcass member by aligning a plurality of pieces of cords and passing them through a die for topping with an extruder provided in the vicinity thereof, thereby, topping rubber to the cord rows to form into a strip-like shape, cutting the strip-like member by a predetermined length and successively align to bond the cut pieces on a moving drum or on a conveyer.
However, when the cut pieces of the strip-like member are aligned to bond, it is necessary to align the plurality of pieces of cords and top rubber thereto, an apparatus equipment therefor becomes complicated and expensive, time and labor are taken for cutting the strip-like member after having been topped and bonding the cut pieces, and an amount of operation is remarkably reduced.
Hence, the inventors are going to fabricate efficiently a carcass member aligned with a number of pieces of rubber-coated cords by a method of using, for example, a rubber-coated cord constituted by coating rubber to a single piece of a fiber coat, and cutting a cylindrical member formed by winding the cord in a spiral shape to develop in a width direction or the like.
Meanwhile, in covering to form rubber for a cord to provide the rubber-coated cord, a cord advancing from a rear side of an extrusion forming head of rubber continuously installed to an extruder is passed through a forming path at inside of a die provided to the head and covering rubber on a cord peripheral face in a thin film shape during a time period of passing the forming path to be formed to constitute a predetermined sectional shape.
In this case, although a covering structure can be simplified since rubber is coated to the single piece of cord, considerable high speed formation can be achieved, and a reduction in an operational efficiency can be restrained, on the contrary, when the cord passes through the rubber forming path at inside of the die, a resistance by a friction between rubber coated to be formed on a surface of a cord and an inner wall face of the path is increased, high speed formation is restrained and an increase in a production efficiency cannot be desired.
Further, although a rubber member of an inner liner or the like of a tire is formed by spirally winding a ribbon-like rubber member a section of which is constituted by a flat crescent shape or a trapezoidal shape on a forming drum, even in a case of extruding to form the ribbon-like rubber member used therefor, there is a limit in increasing a forming speed by a resistance by a friction between an outer peripheral face of the rubber member and an inner wall face of the path at inside of the die of the extrusion forming head and a further increase in the speed is desired.
Patent Reference 1: JP-A-2002-321267
Patent Reference 2: JP-A-2005-28688